Bistrot Zinc has been a popular Chicago restaurant for 16 years, and we count a lot of regulars among our customers. Many of them come back for the bistro classics— Steak Frites, roast chicken, sauteed trout—so we never take those off the right side of the menu. But both regulars and new guests like to try something different sometimes, so the left side changes monthly. Here’s where I incorporate seasonal ingredients and experiment with more contemporary preparations. In September, for example, I’m menuing griddled bucheron cheese with peaches and balsamic as an appetizer and grilled salmon with carrot-leek ragout as an entrée. I believe our sales growth of 6 to 10 percent annually is partly attributed to that menu balance.